Schedule No. 12 


April 11, 1919 


DEPARTMENT OF THE INTERIOR 

FRANKLIN K. LANE, Secretary 

BUREAU OF MINES 

VAN. H. MANNING, Director 


PROCEDURE FOR ESTABLISHING A LIST 
OF PERMISSIBLE SINGLE-SHOT 
BLASTING UNITS 

CHARACTER OF TESTS, CONDITIONS 
UNDER WHICH THE UNITS WILL BE 
TESTED, AND FEES 


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WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1919 



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The Bureau of Mines, in carrying out one of the provisions of its organic act—to 
disseminate information concerning investigations made—prints a limited free edi¬ 
tion of €>ach of its publications. 

When this edition is exhausted, copies may be obtained at cost price only through 
the Superintendent of Documents. Government Printing Office, Washington. D. C. 

The Superintendent of Documents is not an official of the Bureau of Mines. His 
is an entirely separate office and he should be addressed: 

Superintendent of Documents. 

Government Printing Office, 

Washington. D. C. 

The general law under which publications are distributed prohibits the giving of 
more than one copy of a publication to one person. The price of this publication 
is 5 cents. 


First edition. April , 1918, 


Of b, 

APR 30 J9jg 


2 



PROCEDURE FOR ESTABLISHING A LIST OF PERMISSIBLE SINGLE-SHOT 
BLASTING UNITS; CHARACTER OF TESTS, CONDITIONS UNDER WHICH 
THE UNITS WILL BE TESTED, AND FEES. 


PRELIMINARY STATEMENT. 

\ 

AUTHORIZATION. 

An act of Congress (37 Stat., 681) approved February 25, 1913, 
contains the following provision in regard to tests or investigations 
performed by the Bureau of Mines: 

That, for tests or investigations authorized by the Secretary of the Interior under 
the provisions of this act, other than those performed for the Government of the 
United States or State governments within the United States, a reasonable fee cover¬ 
ing the necessary expenses shall be charged according to a schedule prepared by the 
Director of the Bureau of Mines and approved by the Secretary of the Interior, who 
shall prescribe rules and regulations under which such tests or investigations may be 
made. All moneys received from such sources shall be paid into the Treasury to the 
credit of miscellaneous receipts. 

The Bureau of Mines is prepared at its Pittsburgh experiment sta¬ 
tion to conduct tests of single-shot blasting units for use in gaseous 
mines and other similar work. This schedule of tests is issued for the 
information of those who may desire to submit equipment for test. 

DEFINITION OF ‘ ‘ PERMISSIBLE . 9i 

The Bureau of Mines considers a single-shot blasting unit to be 
permissible for use if the details of the construction of the unit are the 
same in all respects as those tested and approved by the bureau in 
accordance with this schedule. 

CONDITIONS UNDER WHICH SINGLE-SHOT BLASTING UNITS WILL BE 

TESTED. 

The conditions under which the Bureau of Mines will examine and 
test single-shot magneto and battery blasting units to establish their 
permissibility are as follows: 

1. The tests will be made at the experiment station of the Bureau 
of Mines at Pittsburgh, Pa. 

2. Applications for tests shall be addressed to the Director, Bureau 
of Mines, Washington, D. C., and shall be accompanied by a complete 

109095 —19 3 



4 


PERMISSIBLE SINGLE-SHOT BLASTING UNITS. 


description of the equipment to be tested and a full set of the draw¬ 
ings mentioned below: 

A drawing or drawings clearly showing the character, size, and rela¬ 
tive arrangement of the complete unit. The drawing or drawings 
shall specify the material of which all parts are made. 

A drawing or drawings showing in detail the safety features. 

A copy of the description, a duplicate set of the drawings, and one 
complete unit shall be sent to the electrical engineer.. Bureau of 
Mines, 4800 Forbes Street, Pittsburgh, Pa. 

3. As soon as possible after receipt of his application for test the 
manufacturer will be notified of the date on which his equipment will 
be tested and the amount of any additional material that will be 
necessary for him to submit. 

4. All material for test shall be delivered by the manufacturer to 
the electrical engineer, Bureau of Mines, 4800 Forbes Street, Pitts¬ 
burgh, Pa., not less than one week prior to the date set for the test. 

5. No unit will be tested unless it is in the completed form in which 
it is to be put on the market. 

6. No one is to be present at the test of a unit except the necessary 
Government officers, their assistants and representatives of the manu¬ 
facturer. The latter shall be present as observers only. 

The conduct of the tests shall be entirely in the hands of the 
bureau’s engineer in charge of the investigation. While the tests are 
in progress the manufacturer’s representatives shall not make unso¬ 
licited suggestions or criticisms of the method of conducting the test. 

7. The tests will be made in the order of the receipt of application 
for test, provided that the necessary material is submitted at the 
proper time. 

8. The details of the results of the tests shall be regarded as con¬ 
fidential by all present at thi| tests and shall not be made public in 
any way prior to their official!publication by the Bureau of Mines. 

requiremAits for approval. 

The requirements that a single-shot blasting unit must have, to 
pass successfully the inspection and tests required by the bureau, are 
stated below: 

UNITS OF THE BATTERY TYPE. 

If the unit is of the battery type, the battery shall be inclosed in an 
efficiently locked casing designed only for shot-firing service. Com¬ 
bination units designed for both blasting and illumination will not be 
approved. 

The outer casing must be mechanically strong and cover the battery 
terminals in such a way that there is no possibility of completing a 
circuit except by plugging into an approved receptacle. 




PERMISSIBLE SINGLE-SHOT BLASTING UNITS. 


5 


The receptacle and plug must be so designed that contact to both 
battery terminals is made simultaneously and that immediately after 
the shot, the plug shall be projected free from its receptacle. 

Four complete units shall each be dropped at least 20 times upon a 
concrete floor from a point 3 feet above it, unless failure occurs before 
the completion of 20 tests. The average number of times that a unit 
may be dropped without failure shall be not less than 10. The 
minimum number of times that a unit may be dropped before failure 
shall be 6. 

A unit shall be considered as having failed if the battery casing be 
cracked, if there are loose electrical connections or if for any reason 
the unit can not give its normal service. 

After a shelf depreciation test of six months, battery-type units 
must be capable of firing 500 bridges equivalent to those in general use 
in a No. 6 electric detonator through 600 feet of double circuit No. 14 
Brown & Sharpe gage copper wire, one bridge being fired at a time. 
Storage battery units may be completely charged before this test. 

The batteries or battery casings shall be so designed and constructed 
that they will not spill or leak electrolyte throughout a seven-hour 
test, during which they will be placed in any position or sequence of 
positions that in the opinion of the bureau’s engineers will be most 
likely to prove whether or not the electrolyte can be spilled under 
service conditions. 

The batteries shall not have short-circuit currents in excess of the 
following values: Batteries giving 2.5 volts or less, 125 amperes; for 
batteries giving more than 2.5 volts but not more than 4 volts, 85 
amperes; batteries giving more than 4 volts but not more than 5 
volts, 65 amperes; for batteries giving more than 5 volts but not 
more than 6 volts, 45 amperes. 

Batteries whose short-circuit currents do not exceed these values 
will be considered satisfactory, in that respect for blasting units. 

UNITS OF THE MAGNETO TYPE. 

If the unit is of the magneto type, the magneto casing must be 
mechanically strong and must have an efficient lock or other adequate 
means of preventing the operation of the magneto except through the 
use of an approved device. 

The device that operates the magneto shall be separate from the 
magneto and so arranged that it is entirely disconnected from the 
magneto after each shot. ? 

This type of blasting unit shall be .subjected to the following service 
tests: The magneto shall be operated five thousand (5,000) times 
after which it shall fire, without fail, when operated in an ordinary 
manner, at least 25 bridges equivalent to those in general use in a 



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6 PERMISSIBLE SINGLE-SHOT BLASTING UNITS. 

No. 6 electric detonator (fired one at a time through 600 feet of No. 14 

Brown & Sharpe gage twin copper wire). 

In accordance with the bureau’s experimental data on the ignition 
of mine gas by sparks (Technical Paper No. 47), the magneto shall 
have a maximum current capacity of not more than 10 amperes and 
a maximum pressure at its terminals of not more than 20 volts. 

Four complete units shall each be dropped at least 20 times upon a 
concrete floor from a point 3 feet above it, unless failure occurs before 
the completion of 20 tests. The average number of times that a unit 
may he dropped without failure shall be not less than 10. Lhe mini¬ 
mum number of times that a unit may be dropped before failure shall 
be 6. 

A unit shall be considered as having failed if the casing is materially 
distorted, if there are loose electrical connections, or if for any reason 
the unit will not give its normal service. 

DESIGN AND CONSTRUCTION. 

The excellence of the mechanical and electrical features of the design 
and construction of blasting units will be considered with special refer¬ 
ence to the reliability of operation and durability of parts. 

All parts shall be constructed of suitable material of the best quality 
and assembled in a substantial manner. 

All electrical contacts shall be so designed, installed, and protected 
that their proper operation will not be prevented by moisture. 

APPROVAL OF PERMISSIBLE SINGLE-SHOT BLASTING UNITS. 

NOTIFICATION OF MANUFACTURER. 

As soon as the bureau’s engineers are satisfied that a blasting unit 
is permissible the manufacturer and the mine inspection departments 
of the several States shall be notified to that effect. As soon as a 
manufacturer receives formal notification that his unit has passed 
the tests prescribed by the bureau he shall be free to advertise such a 
unit as permissible. 

SCOPE OF APPROVAL. 

The bureau’s approval of any blasting unit shall be construed as 
applying to all units made by the same manufacturer that have the 
same construction in the details considered by the bureau, but to no 
other units. Manufacturers shall, before claiming the bureau’s 
approval for any modification of any approved blasting unit, submit to 
the bureau drawings that shall show the extent and nature of such 
modifications, in order that the bureau may decide whether or not it 
should test the remodeled unit before approving it. 


PERMISSIBLE SINGLE-SHOT BLASTING UNITS. 


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APPROVAL PLATES. 

The manufacturers will be required to attach securely to the 
battery casing of each permissible equipment an approval plate 
bearing the seal of the Department of the Interior, Bureau of 
Mines, and inscribed as follows: 


PERMISSIBLE SINGLE-SHOT BLASTING 
UNIT. 

APPROVED FOR SAFETY, RELIABILITY, AND DURABILITY. 
Approval No.issued to.Co. 


The requirement of a separate approval plate will not be made 
where an equally satisfactory inscription can be made by stamping 
the casing. 

WITHDRAWAL OF APPROVAL. 

The bureau reserves the right to rescind, for cause, at any time, 
any approval granted under the conditions herein set forth. 

FEES. 

The following schedule of fees has been established and approved 
for investigations of single-shot blasting units: 

Fee for complete investigation for approval of unit submitted, $75. 

SEGREGATED CHARGES. 

For units of the battery type. 


Preliminary inspection.$10. 00 

Battery dropping test. 10. 00 

Battery short-circuit tes 1 . 5. 00 

Battery spilling test. 5. 00 

Battery service test. 40. 00 

Final inspection. 5. 00 


For units of the magneto type. 

Preliminary inspection. • . 

Maximum and minimum service tests. 

Dropping test.. 

Final inspection. 


REMITTANCES. 

Manufacturers who submit blasting units for tests to determine 
permissibility will be required to furnish certified check or bank 
draft made payable to the Secretary of the Interior, to cover the 
total fees required for the desired tests. Such fees must be received 
at least two weeks prior to the date set for beginning the tests, 
otherwise the equipment of the next applicant upon the list will be 
tested. 


75. 00 

$ 10 . 00 
50. 00 
10. 00 
5. 00 


75 00 

















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PERMISSIBLE SINGLE-SHOT BLASTING UNITS. 

SYNOPSIS OF PROCEDURE TO BE FOLLOWED IN MAKING APPLICATION 

FOR TESTS, SUBMITTING MATERIAL, CONDUCTING TESTS, AND NOTI¬ 
FYING APPLICANT OF RESULTS. 

1. Application for tests should be addressed to the Director of the 
Bureau of Mines, Washington, D. C. This application should be 
accompanied by check or draft and by a complete description of the 
equipment to be tested and a set of the drawings described in para¬ 
graph 1, page 4. Duplicate copies of the application, description, 
and drawings should be sent to the electrical engineer, Bureau of 
Mines, 4800 Forbes Street, Pittsburgh, Pa., accompanied by a single 
complete blasting unit. 

2. As soon as the application has been reviewed by the bureau's 
engineers the applicant will be notified of the date of test and the 
further equipment that it will be necessary for him to submit. 

3. After receiving this notification the applicant should send the 
material required to the electrical engineer, Bureau of Mines, 4800 
Forbes Street, Pittsburgh, Pa. This material must be delivered to 
the address above not less than one week in advance of the date set 
for the beginning of the tests. At this time the applicant should 
state the name and address of the applicant’s representatives who 
will witness the tests. 

4. The tests will be begun on the date set and continued until the 
unit is approved, rejected, or withdrawn. In case a unit is with¬ 
drawn by a manufacturer before an investigation has been com- 
pleted, fees will be charged hi accordance with the work performed 
at the time of withdrawal. Any surplus funds over and above that 
covering tests made will be refunded upon due notification from the 
manufacturer that no more tests are contemplated. 

5. After the bureau’s engineers have considered the results of the 
tests, a formal report of the approva or disapproval of the unit will 
be made to the applicant in writing by the Director of the Bureau of 
Mines. No verbal report will be made and the details of the tests 
must be regarded as confidential by all present. 

Van. H. Manning, 

director. 

Approved April 11, 1919. 

John W. Ha blow 7 ell, 

Assistant to the Secretary 

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